21864875049 has 10 divisors (see below), whose sum is σ = 32662344330. Its totient is φ = 14576583312.

The previous prime is 21864875027. The next prime is 21864875063. The reversal of 21864875049 is 94057846812.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21056041449 + 808833600 = 145107^2 + 28440^2 .

It is not a de Polignac number, because 21864875049 - 2¹³ = 21864866857 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21864874986 and 21864875004.

It is not an unprimeable number, because it can be changed into a prime (21864875069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 134968284 + ... + 134968445.

It is an arithmetic number, because the mean of its divisors is an integer number (3266234433).

Almost surely, 2^21864875049 is an apocalyptic number.

It is an amenable number.

21864875049 is a deficient number, since it is larger than the sum of its proper divisors (10797469281).

21864875049 is an equidigital number, since it uses as much as digits as its factorization.

21864875049 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269936741 (or 269936732 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 21864875049 in words is "twenty-one billion, eight hundred sixty-four million, eight hundred seventy-five thousand, forty-nine".